| Date: | 2000-04-12 17:16:00 | |
| Sender: | Julie Horvath, NASA SLR <Horvath, Julie E. <Julie.Horvath@honeywell-tsi.com>> | |
| Subject: | [SLR-Mail] No. 588: Header Line changed in HTSI Daily Acquisition Data | |
| Author: | Julie Horvath, NASA SLR | |
| Content: | ******************************************************************************** SLR Electronic Mail 2000-04-12 17:16:00 UTC Message No. 588 ******************************************************************************** Author: Julie Horvath, NASA SLR Subject: Header Line changed in HTSI Daily Acquisition Data Dear Colleagues, As many of you are already aware, the daily Tuned IRV header line has been changed from IRVSATSC to IRVSHTSI but also, the quality of the IRVs have greatly increased. These changes were made for a couple of reasons. Following the start of daily TIV distribution to the global network, Roger Wood and Philip Gibbs, from NERC, pointed out an issue with the daily data. The IRVs showed a significant daily time bias drift. During the investigation, we uncovered a difference in our software between our old weekly method to that of the new daily predicts. The new software was applying polar motion in the generation of the IRVs. Since software on station was not expecting this application of polar motion, time bias drifts of upwards of 30 millisecs, were induced in the processing of the IRVs. Since this problem has been corrected, and the application of polar motion has been eliminated, time bias drift has been reduced to approximately 2-4 millisecs per day. Since we recompiled our software in the correction of this problem, we also changed the header record from ATSC to HTSI to accommodate the new corporate name. We are very sorry that this message is late, but we thought that it was much more important to correct the data and ensure that the data was not compromised by the change. As an additional item, beginning today, the CDDIS will change the filename of the daily IRVs from ”.atsc” to ”.htsi”. Regards, Julie Horvath NASA SLR julie.horvath@honeywell-tsi.com (301)805-3951 From: ”Horvath, Julie E.” ******************************************************************************** |